Key Principles of Process Safety for:
Incident Investigation
KP3 - II, Oct 2023
Copyright 2023 American Institute of Chemical Engineers
www.aiche.org/ccps
Acknowledgments
The American Institute of Chemical Engineers (AIChE) and the Center for Chemical Process Safety (CCPS)
express their appreciation and gratitude to all members of the Golden Rules of Process Safety for Key
Principles project subcommittee for their generous efforts in the development and preparation of this
important work. CCPS also wishes to thank the subcommittee members’ respective companies for
supporting their involvement during the different phases in this project.
Core Team Members:
Denise Chastain-Knight, Chair
Della Mann, Vice Chair
Warren Greenfield, Project Consultant
Denise Albrecht
Kevin Campbell
Walt Frank
Anil Gokhale
Mike Hazzan
Ng Ern Huay
Pete Lodal
Frank Renshaw
Louisa Nara
Linda Bergeron
Jeff Fox
Curtis Clements
exida
CCPS Emeritus
CCPS Consultant
3M
Shell
CCPS Emeritus
CCPS Staff
Acutech
Petronas
D&H Process Safety
CCPS Emeritus
CCPS Staff
CCPS Emeritus
CCPS Emeritus
Chemours
Sub Team Incident Investigation Key Principles Team Members:
Mike Broadribb, Lead
Eric Atkins
Amy Gay
Ammar Alkhawaldeh
Mike Hazzan
Della Mann
Denise Albrecht
Warren Greenfield, Project Manager
BakerRisk
OLIN
Occidental Petroleum
BASF
AcuTech
CCPS Emeritus
3M
CCPS Consultant
The collective industrial experience and knowledge of the team members make this guideline
especially valuable to those who develop and manage process safety programs and management systems.
Before publication, all CCPS guidelines are subjected to a peer review process. CCPS gratefully
acknowledges the thoughtful comments and suggestions of the peer reviewers. Their work enhanced the
accuracy and clarity of this guideline.
Copyright: American Institute of Chemical Engineers
Peer reviewers for the Key Principles of Process Safety for Incident Investigation:
Jerry Forest
John Herber
Della Mann
Denise Albrecht
Celanese
Process Hazards Management
CCPS Emeritus
3M
Although the peer reviewers provided comments and suggestions, they were not asked to endorse
this guideline and did not review the final manuscript before its release.
The Center for Chemical Process Safety was established by the American Institute of Chemical Engineers
in 1985 to focus on the engineering and management practices to prevent and mitigate major incidents
involving the release of hazardous chemicals and hydrocarbons. CCPS is active worldwide through its
comprehensive publishing program, annual technical conference, research, and instructional material for
undergraduate engineering education. For more information about CCPS, please call (+1) 646-495-1371,
e-mail ccps@aiche.org, or visit www.aiche.org/ccps
This document is made available for use with no legal obligation or assumptions. Corrections, updates,
and recommendations should be sent to CCPS at ccps@aiche.org
If you are reading this offline, you may not be reading the latest version. Please check on the CCPS
website for the current release. https://www.aiche.org/ccps/tools/golden-rules-process-safety
It is sincerely hoped that the information presented in this document will lead to an even more
impressive safety record for the entire industry; however, neither the American Institute of Chemical
Engineers, its consultants, CCPS Technical Steering Committee and Subcommittee members, their
employers, their employers' officers and directors, and its employees warrant or represent, expressly or
by implication, the correctness or accuracy of the content of the information presented in this
document. As between (1) American Institute of Chemical Engineers, its consultants, CCPS Technical
Steering Committee and Subcommittee members, their employers, their employers' officers and
directors, and its employees and subcontractors, and (2) the user of this document, the user accepts any
legal liability or responsibility whatsoever for the consequence of its use or misuse.
Copyright: American Institute of Chemical Engineers
Key Principles of Process Safety for Incident Investigation
Table of Contents
Key Principle #1:
Know when an event is a process safety incident or a near miss.................................................... 3
Key Principle #2:
Develop and implement a written procedure to investigate process safety incidents and near misses 6
Key Principle #3:
The Investigation Team should consist of an appropriate number of trained and competent members
.............................................................................................................................................. 8
Key Principle #4:
Follow-up on process safety incident investigations by developing and resolving recommendations
into final actions, and implementing the actions in a timely manner ............................................ 10
Key Principle #5:
Learn from Process Safety and Near Miss Incidents .................................................................... 14
References and Supplemental Readings .................................................................................................................... 16
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Key Principles of Process Safety for Incident Investigation
This monograph addresses Incident Investigation, which is a key element of Risk Based Process Safety (RBPS)
[1]. The key principles presented reflect good, common, or successful practices and are intended to assist in
the design and implementation of this element. This module is intended to strengthen and support Incident
Investigation programs.
For the purposes of this monograph the following definitions of incidents and near misses are used. These are
derived from the CCPS “Guidelines for Investigating Chemical Process Incidents”, 3 rd Ed. [2]
Incident—an unusual, unplanned, or unexpected occurrence that either resulted in, or had the potential to
result in harm to people, damage to the environment, or asset/business losses, or loss of public trust or
stakeholder confidence in a company’s reputation. Some examples are:
• process upset with potential process excursions beyond operating limits,
• release of energy or materials,
• challenges to a protective barrier,
• loss of product quality control,
An accident is an incident that results in a significant consequence.
Near-miss—an incident in which an adverse consequence could potentially have resulted if circumstances
(weather conditions, process safeguard response, adherence to procedure, etc.) had been slightly different.
Sometimes near misses are referred to as near hits or close calls.
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Key Principles of Process Safety for Incident Investigation
Key Principle #1:
Know when an event is a process safety incident or a near miss
 Why:
Knowing when an event is a possible process safety incident or a near miss is critical for the Risk Based
Process Safety element of Incident Investigation. It is important because it is common practice in
industry to combine all Environment, Health & Safety (EHS) related incidents including the process safety
incidents in one incident management system. This may lead to a lack of recognition of process safety
incidents and their investigation requirements. For example, a process safety interlock that shut down
a piece equipment might not be investigated if no one recognized that this was a near miss. The lack of
investigation may result in repeated reoccurrences of process transients or other upset events that
become normalized. This will decrease the margin of safety, and the opportunity to learn about the root
causes of the event will be lost.
Knowing when an event is a process safety incident or a near miss sets the priority and practice (Refer
to Key Principle #2) for company/facility personnel to follow. The “CCPS Process Safety Metrics - Guide
for Selecting Leading and Lagging Indicators” and “API RP 754 Process Safety Performance Indicators
for the Refining and Petrochemical Industries” provide guidance to identify, classify, and prioritize
process safety incidents and near misses [3] [4].
Investigating a near miss is a good opportunity to learn important lessons without having to suffer the
consequences of an actual incident.
Clearly communicating the criteria for defining a process safety incident or a near miss will enable more
immediate reporting which will provide the following benefits:
Preservation of time-sensitive evidence
Obtaining witness statements before memories fade
Meeting company and regulatory requirements (refer to Key Principle #2).
Incident History:
A refinery did not recognize events that should have been recorded as process safety incidents or
near misses. In 1994, the refinery had an event that involved flammable vapors being released at
ground level from an atmospheric blowdown drum. In 2005, a similar release led to a multi-fatality
explosion [5].
The learning relevant to this Key Principle is:
If the 1994 event had been recognized as a process safety incident, then it might have been
investigated. Knowing when a process safety incident investigation is required, and the
investigation of this precursor event, could have led to measures that could have prevented the
2005 explosion.
On January 9, 2004, a company began manufacturing its first full-scale batch of a gasoline additive
chemical in a new process line. The batch produced an unanticipated exothermic reaction in the
first step. During the processing of additional batches, the facility had quality problems and made
several recipe changes. It was observed that exotherms were warning signs of side reactions
occurring. These exotherms were not considered near misses and, thus, were not evaluated for
their actual and potential severity. On December 19, 2007, during the production of another batch,
an explosion occurred, resulting in 4 fatalities and 13 injuries [6].
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Key Principles of Process Safety for Incident Investigation
Key Principle #1: Know when an event is a process safety incident or a near miss
The learning relevant to this Key Principle is:
If these exotherms had been identified as near misses, then a process safety incident
investigation might have been initiated. The investigation could have identified measures to
mitigate and possibly prevent the actual incident in 2007.
Incident: On February 20, 2003, an oven had a malfunctioning temperature controller that caused
the oven to overheat. The oven door was left open to help control the temperature. At the same
time, workers cleaning the area created a dust cloud of phenolic resin powder. A history of small
oven fires that had been routinely extinguished by plant personnel using extinguishers and hoses
had not been investigated. Investigators concluded that on February 20, 2003 a fire developed
inside the oven and ignited the dust cloud. The resulting dust explosion and fire set off subsequent
explosions and destroyed much of several production lines. There were 37 injured and 7 fatalities.
The learning relevant to this Key Principle is:
The company was aware of the fire and explosion risks of combustible dust but did not formally
investigate small fires or explosions, nor did they communicate the importance of these events
to the staff. Company memoranda and safety committee meeting minutes from 1992 to 1995
showed concerns with creating explosive dust hazards. The company missed making the staff
aware of the possible dust explosion hazard of phenolic resins and missed conducting a near
miss incident investigation [7].
 How – Leadership:
Leadership should:
Provide a clearly documented definition for a process safety incident and a near miss [8] [4].
Provide a tool to help classify events as a process safety incident or a near miss and to clarify when an
event should be investigated [4].
Provide training to all facility personnel on how to recognize and report process safety incidents and
near misses. They should provide more detailed training on incident investigation methods and
techniques to personnel who might be assigned to incident investigation teams.
Promote and encourage reporting occurrences regardless of whether they are investigated. Personnel
should not have concerns that any occurrence that they report will negatively influence personnelrelated considerations such as promotions, assignments, bonuses, or job security.
Provide necessary resources (including software tools) to allow the efficient reporting and investigating
of process safety incidents and near misses. They should demonstrate a visible leadership interest in
the actual and potential risk of incidents and near misses and continuously improve the incident
investigation process so that more incidents are investigated and more and better lessons learned are
shared.
Maintain metrics to monitor the effectiveness of the incident and near miss reporting system. [9] [3]
[10] [11].
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Key Principles of Process Safety for Incident Investigation
Key Principle #1: Know when an event is a process safety incident or a near miss
 How – Implementers/ Users:
Learn the differences between an event, a process safety incident, and a near miss through training
(informal or formal), reviews of work experiences where incidents or near misses have occurred, or use
of posted materials that constantly remind personnel of these important distinctions. Employees can
learn the normal and abnormal events that could create a process safety incident or near miss by
participating in Process Hazard Analyses (PHAs). Deviations from normal operation (e.g. human error)
may become a process safety incident or near miss [12]. The PHA should enable better recognition of
potential process safety incidents and near misses because the PHA hazard scenarios (i.e. cause and
consequence) may be outside of acceptable operating conditions.
Ask subject matter experts who are knowledgeable in the process safety incident investigation process
if the event is a normal event, a process safety incident or a near miss.
Understand the mechanics and timing requirements of the process safety incident and near miss
reporting system.
Report all events that are possible process safety incidents or near misses.
Watch for abnormal occurrences that become normalized because they did not result in any adverse
consequences [12].
 Supplemental Reading: [1] [2] [3] [4]
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Key Principles of Process Safety for Incident Investigation
Key Principle #2:
Develop and implement a written procedure to investigate process safety
incidents and near misses
 Why:
A well-executed and documented process safety incident investigation procedure will provide a
consistent and repeatable process to enable collecting evidence, analyzing and identifying causal factors,
identifying root causes, and developing recommendations.
The practice of having a well-executed and documented incident investigation procedure should help
ensure that lessons are learned and applied to support safe and reliable operations.
 How – Leadership:
Leadership should:
Support the development and approve an incident investigation procedure that provides guidance to
organize, execute, document, follow-up, and communicate the investigation of process safety incidents
and near misses.
Reinforce the consistent implementation of the incident investigation program across the site or
company.
Ensure adequate resources have been allocated for the incident investigation program.
Remove barriers to enable transparency for conducting a thorough investigation; e.g., ensuring the
objectivity of the investigation team, and restricting the influence of stakeholders who fear being blamed
[13] [14].
Establish a training program for incident investigation team leaders and team members.
Include incident investigation key performance indicators in the process safety metrics program [3] [10]
[11].
Establish a system to track and manage incident investigation recommendations. This may be part of
an overall process safety recommendations tracking system or a separate system.
 How – Implementers/ Users:
Develop a dependable process safety incident investigation procedure that includes the following: [2,
pp. 47-77], [14]:
Definition of a process safety incident or near miss (Refer to Key Principle #1). Examples can be
useful to illustrate when an event is/is not a process safety incident or near miss.
Reporting of events which have the potential to be a process safety incident or near miss. If the
event is required to be reported to a government agency, the specific reporting time limits and
reporting format/content should be included in the incident investigation procedure.
Develop criteria on when to initiate a process safety incident or near miss investigation.
Responsibilities and competencies required for the various roles in the incident investigation
program.
Establishing the boundary/scope of the incident under investigation.
Choices for an appropriate technique of investigation based upon the actual and potential severity
classification of the process safety incident or near miss. Commonly available investigation
techniques vary in complexity depending on the complexity and severity of the incident or near
miss.
Selection of the incident investigation team, including contractors where they were involved in the
incident. Avoid conflicts of interest where possible (Refer to Key Principle #3) [14]
Practices for securing the incident scene, collecting evidence, and determining when the area is safe
for the field investigation to begin. Practices and methodologies to preserve, gather, analyze and
log evidence include:
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Key Principles of Process Safety for Incident Investigation
Key Principle #2: Develop and implement a written procedure to investigate process safety
incidents and near misses
Protocols for tasks such as sampling, equipment testing, and any other changes to the
site/evidence.
Obtain agreement to the protocols with relevant parties before collecting evidence.
Evidence custody transfer system, as necessary should evidence testing by an independent third
party be required.
Evidence including operating data from the data historian, security camera video, photographs,
and samples of released materials or debris, drone fly-overs, and other records [2].
Interviewing witnesses and taking their statements.
Identifying and collecting relevant records and documents.
Preserving physical evidence so that it is not compromised.
Timeline development
Methodology for conducting the root cause analysis. [15]
Incident Report including its format, content, review, and approval. The report should reside in an
archive system and have a specified retention period. In some cases, there may be a protocol for
handling confidential and privileged data.
Tracking and managing incident investigation recommendations through to their implementation.
Communication of lessons learned from the incident investigation to the affected personnel including
contractors, including information relevant to other process safety elements such as operating
procedures, training, asset integrity, etc. (See Key Principle #5).
External communications, where appropriate. For example, it may be necessary to communicate
the results of an incident investigation to external regulators based on a valid order issued by a
regulatory agency.
Monitoring and trending of process safety incidents to identify reoccurring types
Communication to the facility’s Process Hazard Analysis program manager so the incident event
scenario can be analyzed during the next revalidation.
Implement and follow the written incident investigation procedure.
Witness interviews should be conducted early, before witnesses forget details or are able to discuss
the event with others.
Incident investigation team members collect evidence, conduct interviews, perform root cause
analysis and write the incident investigation report, as assigned.
Placing and assuring that the equipment is in a safe and stable condition so that investigation
activities in the field can be performed safely
Participate in the incident investigation, as assigned. Most investigations involve interviewing
operations and maintenance personnel who were likely in the field when the incident began and
have first-hand knowledge of some of the contributing factors of the incident.
Report process safety incidents and near misses when they observe events that warrant reporting.
Understand and comply with field evidence preservation requirements when assigned to collect
evidence. Keep investigation records (e.g. witness statements, data sheets) to ensure that data is
secured.
Provide engineering support to the investigation team, such as engineering calculations, simulation, or
modeling.
 Supplemental Reading: [2] [6] [14] [16] [17]
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Key Principles of Process Safety for Incident Investigation
Key Principle #3:
The Investigation Team should consist of an appropriate number of trained
and competent members
 Why:
Providing for the appropriate number of trained and competent people on the incident investigation
team should allow for a more efficient, focused, and in-depth incident investigation. It will help ensure
that:
The incident investigation leader is formally trained as an incident investigation leader as a minimum.
The team members should also be trained in incident investigation for significant incidents [2] [18]
[19] [20].
Team members are competent in their area of expertise [18] [19].
The selected investigation methodologies are understood and applied consistently [14].
There is an understanding of the technology of the process and the equipment.
There is an objective and unbiased analysis of the incident [2].
The causal factors, root cause(s) and recommendation(s) are identified to prevent the incident’s
reoccurrence [2].
There will be a complete and effective documentation and report [2] [14].
Process safety incident investigations team size should be commensurate with the complexity of the
investigation [1].
Incident History:
A Polyamide Unit produced a high-performance nylon, and it had experienced polymer reaction
incidents (waste polymer fires and explosions) from its initial startup in 1993 to 2001. In 2001, the
end plate of the Polymer Catch Tank blew off, fatally striking three employees during preparations
to clean the vessel that was full of decomposing waste polymer [21]. Although the prior incidents
had been investigated, the investigation teams had not adequately identified the controls required
to prevent reoccurrence. No one on the prior investigation team understood that the process design
did not identify this reactive hazard. Process instrumentation and vessel opening practices failed to
provide adequate warnings of the state of the material inside.
The learning relevant to this Key Principle is that:
The multiple investigation teams did not have process engineering expertise sufficient to identify
the reactive chemistry hazard and, therefore, could not identify how to control the hazard. There
were witnesses who described the molten cores of exploded pods as they discolored, which is
consistent with decomposition. A competent investigation team could have recognized that a
significant hazard was associated with accumulating large quantities of molten polymer,
including waste in the polymer catch tank, which created a reactivity hazard.
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Key Principles of Process Safety for Incident Investigation
Key Principle #3: The Investigation Team should consist of an appropriate number of trained and
competent members
 How – Leadership:
Leadership should:
Ensure that initial training for lead investigators and team members is conducted.
Ensure that refresher or ongoing training for lead investigators and team members is conducted.
Ensure that those participating on the investigation team are competent in the expertise function that
they are providing.
Ensure that the investigation team members are allowed the time required to support the investigation.
Ensure, to the extent possible, that the incident investigation teams are impartial. This will help ensure
that there is an objective and unbiased analysis of the incident [2].
 How – Implementers / Users:
Provide the appropriate number of trained and competent people so that:
The investigation team has all of the needed technical expertise to ensure that the incident or near
miss is investigated thoroughly.
The incident investigation leader is formally trained.
The team members are trained in the incident investigation activities that they will perform. For
example, team members who will conduct formal interviews of witnesses should receive training in
how to conduct witness interviews. [2] [18] [19] [20]
The incident investigation leader and team members are objective and unbiased.
The selected investigation methodologies are understood and applied consistently by the team and
applied consistently. [14]
The team members have a basic understanding of the technology of the process and the equipment
design and operation. However, additional technical support may be necessary to supplement the
incident investigation team’s expertise.
The correct causal factors and root cause(s) are identified. [2]
The recommendations to prevent the incident’s reoccurrence are formulated.
The incident investigation report can be produced. [2] [14]
Process safety incident investigations team size should be commensurate with the complexity of the
investigation. The actual number is dependent on factors such as the nature and severity of the
incident. [1]
Participate in the Incident Investigation (Knowledgeable Operations & Maintenance, Engineers,
Emergency responders, and project representatives, personnel with process safety expertise).
 Supplemental Reading: [2] [14] [22]
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Key Principles of Process Safety for Incident Investigation
Key Principle #4:
Follow-up on process safety incident investigations by developing and
resolving recommendations into final actions, and implementing the actions
in a timely manner
 Why:
Risks from Process Safety Incidents are not reduced until the incident investigation recommendations
are resolved and the action items are completed [2].
Incidents:
The Challenger incident of 1986, as well as several chemical/process industry incidents, including
BP’s Texas City refinery explosion of 2005, occurred, in part, because previous incidents or near
misses had been investigated, but the recommendations from these investigations were not
followed-up adequately. Both the Rogers Commission (on the Challenger incident) and the Baker
Panel (on the BP Texas City incident) noted that precursor events had occurred which were related
to the final catastrophic incidents they investigated. In both cases, the organizations had conducted
investigations of the prior incidents and had generated recommendations to correct the root causes
found, but these recommendations had not been completed. Additionally, recommendations for
process changes not related to a previous incident investigation but based on engineering analysis
and operational experience had been made but not implemented and these recommendations could
have removed or altered the root causes of the final catastrophic events.
For example, the Rogers Commission stated in its final report [23]:
“Morton Thiokol, Inc., the contractor, did not accept the implication of tests early in the program
that the design had a serious and unanticipated flaw. NASA did not accept the judgment of its
engineers that the design was unacceptable, and as the joint problems grew in number and
severity NASA minimized them in management briefings and reports. Thiokol's stated position
was that "the condition is not desirable but is acceptable." Neither Thiokol nor NASA expected
the rubber O-rings sealing the joints to be touched by hot gases of motor ignition, much less to
be partially burned. However, as tests and then flights confirmed damage to the sealing rings,
the reaction by both NASA and Thiokol was to increase the amount of damage considered
"acceptable." At no time did management either recommend a redesign of the joint or call for
the Shuttle's grounding until the problem was solved.”
The Baker Panel drew the following conclusions in its final report [24]:
“The ultimate objective of incident investigation is preventing reoccurrence of a specific
incident scenario or related similar incidents. Considerable effort and resources are expended
in determining an incident’s root causes and identifying suggested preventive measures.
Despite this effort, the potential for a repeat occurrence remains unchanged until
recommendations are implemented. The value of the investigation is entirely dependent on
the effectiveness of follow-up activities.
The team that conducted the review, for example, identified a backlog of unclosed action
items in the tracking databases relating to various aspects of process safety management,
including those stemming from incident investigation. Some of the action items from incident
investigations extended back over a period of more than 12 months.”
The learning relevant to this Key Principle is that:
The failure to promptly resolve recommendations and close/complete the resulting action items
stemming from incident and near miss investigations represents a serious systemic management
system issue. The underlying reasons for this failure (which might also apply not only to incident
investigations, but also to PHAs, audits, and other process safety program elements) should be
thoroughly identified, understood, and corrected. Otherwise, the likelihood of reoccurrence is
higher and the consequences of the reoccurrence could be more severe than the original event.
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Key Principles of Process Safety for Incident Investigation
Key Principle #4: Follow-up on process safety incident investigations by developing and
resolving recommendations into final actions, and implementing the actions in
a timely manner
 How – Leadership:
Leadership should:
Ensure the site/facility has a system for resolving recommendations and tracking action items to
completion. This system may be the same as or separate from the system that is used to resolve and
track other process safety and EHS related recommendations and action items.
Provide appropriate resources to allow the management of recommendations and action items to be
completed in a technically sound manner and as expeditiously as possible. This should include periodic
reviews to monitor the status and progress of recommendation resolution and action item completion.
Assign a due date and a person who is responsible for the resolution of the recommendation(s).
If the completion of the final action items will be delayed, ensure that appropriate interim/temporary
safeguards are implemented as warranted to ensure safe operation during the delay. The temporary
safety measures should be commensurate with the risk that the permanent action item is intended to
abate. Implementation difficulties may be discovered later, requiring due date deferral/extension and
consideration of the need for interim safety measure(s).
Review incident investigation recommendations, and accept, reject, or modify them at an appropriate
level of management to assure the recommendation is an effective resolution and that the risk identified
by the investigation is reduced as much as practicable. The reasons for the rejection or modification of
recommendations should be documented. The appropriate approval level may be a function of the
complexity of the recommendation, or the consequence or severity of the incident. The documented
rationale for rejection or modification could be based on the following criteria (adapted from [25]):
The underlying incident investigation root cause analysis and other work contained factual errors
which resulted in flawed recommendations.
The recommendation was not necessary to protect the health and safety of people, i.e., the
recommendation addressed non-safety or process safety issues such as product quality, production
costs, etc.
An alternative measure that would provide a sufficient level of protection was substituted.
The recommendation was infeasible. When claiming that a recommendation is not feasible the
evidence substantiating such a claim should be documented and an alternate means of mitigating
the risk should be identified and implemented.
Make the decisions regarding which action items are completed, when they are completed, and their
priorities. Leadership approves the projects, work orders, MOCs, or other processes as provided for in
the procedures governing those activities, which should designate an appropriate level of approval
depending upon relevant factors such as the risk being abated, the cost, the impact on production or
operability of the facility or one or more of its processes, or other factors. The approval should also
include assigning and empowering personnel responsible to develop and implement action items for
each incident investigation recommendation.
Clearly assign responsibility for each action item to an individual (not an organizational function) and
should ensure that a system exists for handover of action item responsibilities when organizational
changes occur.
Prepare a plan with target dates for implementation of the final action items. The implementation target
dates should be assigned so that they are “timely.” The following criteria should be applied when
defining “timely:”
The risks incurred if the action item is not completed. For example, there may be an increased
likelihood of reoccurrence with current conditions.
When does “timely” become immediate? Under what conditions should this high priority action be
taken? Normally, the uncorrected risk will be an important criterion to consider in making this
decision.
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Key Principles of Process Safety for Incident Investigation
Key Principle #4: Follow-up on process safety incident investigations by developing and
resolving recommendations into final actions, and implementing the actions in
a timely manner
The length of time is not excessive. A low complexity action item might be completed quickly and
relatively easily. For example, action items involving procedural or administrative changes are easier
and should be quicker than action items that involve equipment changes.
The date is reasonable and defensible. For example, the opportunity for action item completion
might require a process or equipment outage that delays implementation.
The existing trend of meeting target dates. For example, if the current resources do not enable
meeting the target dates then it may be necessary to add resources or to extend the target date.
Care should be exercised with extensions or deferrals of action items. These should be tracked and
managed, along with those action items that are considered overdue to understand the complete
picture of the status of the action items. Track the aging of overdue and deferred action items to
understand the amount of time that has elapsed since they were due for completion.
If the action item involves modifications to equipment, has an opportunity to complete the action
item come and gone without taking any action? For example, has a turnaround occurred and was
an action item that was scheduled for completion during the outage not completed?
If the permanent corrective action cannot be accomplished on schedule or within a reasonable
length of time, can any interim measures be provided to reduce the risk?
Communicate expectations and manage completion of outstanding action items to meet the target due
dates.
Establish a formal process for deferrals or extensions when the completion of action items are overdue.
The deferrals/extensions should be justified by reasons that are reasonable and defensible, and not
based solely on cost considerations. When deferrals/extensions are granted for completion of incident
investigation action items, they should be monitored in facility process safety program metrics [3] [10]
[11].
Communicate action item progress to upper management and/or regulators when needed.
 How – Implementers / Users:
The investigation team should determine and develop initial recommendations to address the root
cause(s) and any contributing causes, and resolve those recommendation(s) to produce final action items
(facility/company) by:
Addressing all of the root causes identified
Incorporating the concept of inherent safety to the extent possible [26]
Preventing future incidents by following this hierarchical philosophy:
Eliminating the hazard where possible
Avoiding the hazard where possible
Identifying changes to the management system governing the element
Avoiding disciplinary or other human resources related action
Avoiding incompletely or vaguely worded recommendations
Entering the recommendation(s) into the facility or company’s incident tracking system, or
alternatively, the tracking system used for all process safety related recommendations
Resolving recommendation(s) using technical reviewers, SME, or other resources to produce the
final action items to prevent the reoccurrence of the incident or near miss
Explicitly documenting what was done to resolve the recommendation
Tracking and managing the final action items in the system used by the facility or company
Implement/complete assigned action items to reduce the risk and prevent reoccurrence of the incident
or near miss by:
Establishing projects, maintenance work orders, MOCs, or other administrative processes to make
any physical changes to equipment or procedures and practices described in the final action items
and schedule those projects or work orders for completion as soon as feasible
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Key Principles of Process Safety for Incident Investigation
Key Principle #4: Follow-up on process safety incident investigations by developing and
resolving recommendations into final actions, and implementing the actions in
a timely manner
Executing those projects or work orders in accordance with facility/company engineering,
construction, and commissioning specifications, standards, and procedures
Documenting the execution of the projects, work orders, MOCs, or other changes in records specified
by administrative procedures governing the activities, including the date the action items were
completed
Do not permit the designation of action items as closed based upon the promise of some future action.
This includes projects, work orders, or MOCs that are approved but not yet executed. A project or other
activity should only be considered complete when the physical changes to equipment or procedures has
been completed and verified.
Perform engineering work to support development and resolution of recommendations and action items
produced by incident investigations.
Implement action items from incident investigations by the target due dates.
If a due date extension is required, submit the request in advance of the due date to allow proper
consideration of alternatives. Have valid reasons for requesting due date extensions.
 Supplemental Reading: [2]
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Key Principles of Process Safety for Incident Investigation
Key Principle #5:
Learn from Process Safety and Near Miss Incidents
 Why:
Process safety incidents cost money.
Process risks are not reduced until the action items to implement incident investigation
recommendations are completed. [2]
Process safety program performance should improve with learning from incidents.
Sharing process safety incident information may prevent another division or company from having to
learn the “hard way” (i.e., learning from their own losses).
Keeping the awareness of process safety incidents in the minds of the workforce should create a sense
of vulnerability and vigilance for warning signs of hazards that can be controlled [27].
A learning culture can improve the design, operation, and maintenance of a process to foster safe and
reliable operations.
Incident History:
A serious fire and explosion occurred at a compressor station involving the failure of a check valve.
A joint EPA/OSHA investigation determined that another incident involving a failed check valve had
occurred, and the company was cited for failure to adequately apply lessons learned from the
previous incident [28].
The learning relevant to this Key Principle is that:
The company’s culture did not assign sufficient priority to learning from prior incidents and, in
this instance, the failure of a check valve reoccurred.
 How – Leadership:
Leadership should:
Approve the level of sharing of facility incident information. Share incident and near miss root causes
and lessons learned internally, and carefully define the level of external sharing. These provisions should
be clearly described in the facility incident investigation procedure.
Include leading and lagging key performance indicators (KPI) of the process safety incident investigation
program in the facility or company process safety program metrics. These KPIs should be collected at a
frequency of approximately 1 – 3 months. Schedule formal reviews of process safety metrics on a
frequent, ongoing basis and generate recommendations to improve incident investigations based on the
trends of the KPIs [3] [10] [11].
Possible incident investigation lagging KPIs include:
number of near misses that were reported (near misses can also be categorized as leading
indicators)
number of incidents that were reported
number of near misses that were investigated
number of incidents that were investigated.
Possible incident investigation leading KPIs include:
number of overdue incident investigation action items
number of deferred incident investigation action items
Establish an open, trusting, and no-blame culture even when human error was identified as a contributor
or root cause. Human error usually indicates lack of training, inadequate procedures, or other
management system failures.
Establish positive reinforcement for recognizing the importance of near misses. Near misses provide an
opportunity to learn valuable lessons without suffering any adverse consequences. They represent early
warning signs of more serious events and they should be thoroughly analyzed for their root causes [27].
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Key Principles of Process Safety for Incident Investigation
Key Principle #5: Learn from Process Safety and Near Miss Incidents
Conduct “safety stand down” sessions when required. A safety stand down is an organized break from
work by which employers hold a safety discussion with their employees. Stand downs can occur at any
time that employers deem it necessary. They are often taken as occasions to discuss safety problems
that have occurred and are either serious or reoccurring while also reinforcing the organizations policies
regarding safety in general.
Consider performing an independent internal review of past incident investigations to determine if the
root cause analysis was complete and if the lessons learned were disseminated adequately.
 How – Implementers/ Users:
Establish a formal process for sharing the lessons learned from incident investigations with relevant
internal personnel whose jobs are affected by the lessons learned. This process should include methods
of presenting the lessons to personnel, e.g., face-to-face briefings, use of other regular forums such as
safety meetings to present them, use of e-mail systems to transmit lessons learned to relevant
personnel, or other methods. The process should also provide for documentation of what was shared,
when it was shared, and who received it.
Establish a process for sharing the lessons learned from incident investigations with relevant external
organizations. For the purposes of this guidance, external organizations can include other sites/facilities
within the same company, as well as organizations outside the company where the incident occurred.
This process should carefully define what “external” means in this context, and this definition should be
carefully reviewed by all relevant groups, disciplines, and relevant individuals within the company before
any external sharing takes place.
Use lessons learned from previous incidents and near misses to maintain and heighten the workforce’s
sense of vulnerability of the risks in their facility. Use the lessons learned in training programs for
operators, maintenance personnel, engineering and project personnel, and others as appropriate.
Frequently “re-tell the story” of higher importance near misses and incidents in order to maintain
corporate memory. Promote communication of process safety incident investigation learnings internally.
These communication forums can include:
Process Safety Bulletins (internal and external)
Toolbox meetings
Video re-enactments
Process Safety Town Halls/ Meetings
Any other event that supports improving process safety culture
Obtain incident reports and use them to include the lessons learned from previous incidents and near
misses when writing and reviewing operating procedures, particularly in warning and cautions
statements.
Obtain incident reports and use the lessons learned from previous incidents and near misses during
operator training activities.
Obtain incident reports and include the lessons learned from previous incidents and near misses in the
emergency response plan and its supporting procedures [29].
Seek and apply lessons learned from other company locations and industry.
 Supplemental Reading: [2] [5] [22] [30]
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Key Principles of Process Safety for Incident Investigation
References and Supplemental Readings
[1] CCPS (Center for Chemical Process Safety), Guidelines for Risk Based Process Safety, Hoboken, NJ: John Wiley and
Sons, 2007.
[2] CCPS (Center for Chemical Process Safety), Guidelines for Investigating Process Safety Incidents, Hoboken, NJ: John
Wiley and Sons, 2019.
[3] CCPS (Center for Chemical Process Safety), "Process Safety Metrics- Guide for Selecting Leading and Lagging
Indicators," CCPS, New York, 2022.
[4] API (American Petroleum Institute), API RP 754 Process Safety Performance Indicators for the Refining and
Petrochemical Industries, 3rd Edition, Washington, D.C.: API (American Petroleum Institute), 2021.
[5] CSB, "Refinery Explosion and Fire, Investigation Report No. 2005-04-I-Tx, BP, Texas City," US Chemical Safety and
Hazard Investigation Board (CSB), Washington, D.C., 2007.
[6] CSB, "T2 Laboratories, Inc. Runaway Reaction, Report No. 2008-3-I-FL," US Chemical Safety and Hazard
Investigation Board (CSB), Washington, D.C., 2009.
[7] CSB, "Combustible Dust Fire & Explosions. Report No. 2003-09-I-KY," US Chemical Safety and Hazard Investigation
Board (CSB), Washington, D.C., 2003.
[8] CCPS (Center for Chemical Process Safety), "CCPS Process Safety Glossary," Center for Chemical Process Safety,
2021. [Online]. Available: www.aiche.org/ccps/resources/glossary.
[9] CCPS (Center for Chemical Process Safety), Guidelines for Integrating Management Systems and Metrics to Improve
Process Safety Performance, Hoboken, N.J.: John Wiley and Sons, 2016.
[10] The American Chemistry Council (ACC), "Performance Metrics Guidance Document," The American Chemistry Council
(ACC), Washington DC, 2014.
[11] International Association of Oil and Gas Producers, "Recommended Practice on Key Performance Indicators," vol.
456, no. November, 2018.
[12] CCPS (Center for Chemical Process Safety), Recognizing and Responding to Normalization of Deviance, Hoboken,
N.J.: John Wiley and Sons, 2018.
[13] CCPS (Center for Chemical Process Safety), Essential Practices for Creating, Strengthening, and Sustaining Process
Safety Culture, Hoboken, NJ: John Wiley and Sons, 2018.
[14] American Petroleum Institute (API), API RP 585 – Pressure Equipment Integrity Incident Investigation – First Edition,
Washington, DC, U.S.A.: American Petroleum Institute (API), 2014.
[15] NFPA, Guide for Fire and Explosion Investigations, NFPA 921, Quincy, MA: National Fire Protection Association, 2017.
[16] CCPS (Center for Chemical Process Safety), "CCPS-Process Safety Incident Evaluation Tool," [Online]. Available:
www. aiche.org/ccps.
[17] CCPS (Center for Chemical Process Safety), Guidelines for Process Safety Documentation, Hoboken, NJ: John Wiley
and Sons, 1995.
[18] US Occupational Safety and Health Administration (OSHA), 29 CFR1910.119 Process safety management of highly
hazardous chemicals, OSHA.
[19] US EPA, 40 CFR68 Chemical Accident Prevention Provisions, Washington, D.C.: US Environmental Protection Agency.
[20] CSA Group, CSA Z 767 2nd edition, Process Safety Management, CSA Group, 2017.
[21] CSB, "Thermal Decomposition Incident, BP Amoco Polymers, Inc., Report No. 2001-03-GA," US Chemical Safety and
Hazard Investigation Board (CSB), Washington D.C., 2002.
[22] CCPS (Center for Chemical Process Safety), Incidents that Define Process Safety, New York: AIChE, 2001.
[23] Rogers Commission, Report to the President by the Presidential Commission On the Space Shuttle Challenger
Accident, June 6, 1986.
[24] Baker Panel, "The Report Of The BP U.S. Refineries Independent Safety Review Panel," (January 2007).
[25] US Occupational Safety and Health Administration (OSHA), OSHA Instruction CPL 2-2.45A, Washington, DC: OSHA,
1994.
[26] CCPS (Center for Chemical Process Safety), Inherently Safer Chemical Processes - A Life Cycle Approach (3rd
Edition), Hoboken, N. J.: John Wiley & Sons, 2019.
[27] CCPS (Center for Chemical Process Safety), Recognizing Catastrophic Incident Warning Signs in the Process
Industries, Hoboken, N.J.: John Wiley and Sons, 2011.
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Key Principles of Process Safety for Incident Investigation
[28] U.S. EPA, Joint Chemical Accident Investigation Report, Shell Chemical Company, Deer Park, Texas, US EPA
document #550-R-98-005,, Washington D.C.: U.S. Environmental Protection Agency, 1998.
[29] CSB, "Toxic Chemical Release at the DuPont La Porte Chemical Facility," US Chemical Safety and Hazard
Investigation Board (CSB), Washington, D.C., 2019.
[30] A. Ness, "Lessons Learned from Recent Process Safety Incidents," CEP, pp. 23-29, March 2015.
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Key Principles of Process Safety for: Incident Investigation
KP3 - II, Oct 2023
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